The XChangeKeyboardControl function controls the keyboard
characteristics defined by the XKeyboardControl structure. The value_mask
argument specifies which values are to be changed.

XChangeKeyboardControl
can generate BadMatch and BadValue errors.

The XGetKeyboardControl
function returns the current control values for the keyboard to the XKeyboardState
structure.

The XAutoRepeatOn function turns on auto-repeat for the keyboard
on the specified display.

The XAutoRepeatOff function turns off auto-repeat
for the keyboard on the specified display.

The XBell function rings the
bell on the keyboard on the specified display, if possible. The specified
volume is relative to the base volume for the keyboard. If the value for
the percent argument is not in the range -100 to 100 inclusive, a BadValue
error results. The volume at which the bell rings when the percent argument
is nonnegative is:

base - [(base * percent) / 100] + percent

The volume
at which the bell rings when the percent argument is negative is:

base
+ [(base * percent) / 100]

To change the base volume of the bell, use XChangeKeyboardControl.

XBell can generate a BadValue error.

The XQueryKeymap function returns
a bit vector for the logical state of the keyboard, where each bit set
to 1 indicates that the corresponding key is currently pressed down. The
vector is represented as 32 bytes. Byte N (from 0) contains the bits for
keys 8N to 8N + 7 with the least significant bit in the byte representing
key 8N.

Note that the logical state of a device (as seen by client applications)
may lag the physical state if device event processing is frozen.

The key_click_percent member sets the volume for key clicks between 0
(off) and 100 (loud) inclusive, if possible. A setting of -1 restores
the default. Other negative values generate a BadValue error.

The bell_percent
sets the base volume for the bell between 0 (off) and 100 (loud) inclusive,
if possible. A setting of -1 restores the default. Other negative values
generate a BadValue error. The bell_pitch member sets the pitch (specified
in Hz) of the bell, if possible. A setting of -1 restores the default. Other
negative values generate a BadValue error. The bell_duration member sets
the duration of the bell specified in milliseconds, if possible. A setting
of -1 restores the default. Other negative values generate a BadValue error.

If both the led_mode and led members are specified, the state of that LED
is changed, if possible. The led_mode member can be set to LedModeOn
or LedModeOff. If only led_mode is specified, the state of all LEDs are
changed, if possible. At most 32 LEDs numbered from one are supported.
No standard interpretation of LEDs is defined. If led is specified without
led_mode, a BadMatch error results.

If both the auto_repeat_mode and
key members are specified, the auto_repeat_mode of that key is changed
(according to AutoRepeatModeOn, AutoRepeatModeOff, or AutoRepeatModeDefault),
if possible. If only auto_repeat_mode is specified, the global auto_repeat_mode
for the entire keyboard is changed, if possible, and does not affect the
per-key settings. If a key is specified without an auto_repeat_mode, a BadMatch
error results. Each key has an individual mode of whether or not it should
auto-repeat and a default setting for the mode. In addition, there is a global
mode of whether auto-repeat should be enabled or not and a default setting
for that mode. When global mode is AutoRepeatModeOn, keys should obey
their individual auto-repeat modes. When global mode is AutoRepeatModeOff,
no keys should auto-repeat. An auto-repeating key generates alternating
KeyPress and KeyRelease events. When a key is used as a modifier, it
is desirable for the key not to auto-repeat, regardless of its auto-repeat
setting.

For the LEDs, the least significant bit of led_mask corresponds to LED
one, and each bit set to 1 in led_mask indicates an LED that is lit. The
global_auto_repeat member can be set to AutoRepeatModeOn or AutoRepeatModeOff.
The auto_repeats member is a bit vector. Each bit set to 1 indicates that
auto-repeat is enabled for the corresponding key. The vector is represented
as 32 bytes. Byte N (from 0) contains the bits for keys 8N to 8N + 7 with
the least significant bit in the byte representing key 8N.

Some argument or pair of arguments has the correct type and range but
fails to match in some other way required by the request.

BadValue

Some
numeric value falls outside the range of values accepted by the request.
Unless a specific range is specified for an argument, the full range defined
by the argument's type is accepted. Any argument defined as a set of alternatives
can generate this error.